The short-term efficacy of high flow nasal oxygen therapy on cardiovascular surgical patients: a randomized crossover trial.

BACKGROUND: Oxygen therapy after extubation in the intensive care unit (ICU) is essential in order to maintain adequate oxygenation, especially in patients who have undertaken cardiovascular surgery. A Venturi mask (VM) has been routinely used as an oxygen therapy in the ICU. Recently, however, the high flow nasal cannula (HFNC) has become available, and this device can deliver up to 60 L/min of humidified oxygen. The aim of this study is to evaluate the short-term efficacy between HFNC and VM in cardiovascular surgical patients. METHODS: Forty patients who underwent cardiovascular surgery were randomized to either protocol A (HFNC followed by VM) or protocol B (VM followed by HFNC). After 60-minutes of use with either device, arterial blood gas analysis was performed, and the PaO2/FiO2 ratio (PFR) was calculated. Simultaneously, physiological data (respiratory rate, heart rate, mean arterial pressure, continuous cardiac index, and mixed venous oxygen saturation) were recorded. During this procedure, FiO2 and gas flow were maintained at a fixed rate. These variables were compared by using the paired t-test, and a p value < 0.05 was considered significant. All data were expressed as mean (standard deviation). RESULTS: Thirty-five patients (17 from protocol A and 18 from protocol B) were enrolled, and 5 patients were excluded from analysis in accordance with the exit criteria. PaO2 was significantly higher in the HFNC group than in the VM group [101.7 (25.9) vs. 91.8 (23.0), mean difference 9.87 (18.5), 95% confidence interval 3.5 to 16.2, p = 0.003]. Moreover, PFR was significantly higher in the HFNC group than in the VM group [265.9 (81.4) vs. 238.7 (68.5), p = 0.002]. Moreover, PaCO2 was significantly lower in the HFNC group than in the VM group [33.8 (3.5) vs. 34.7 (2.9), p = 0.033]. The respiratory rate was significantly lower in the HFNC group than in the VM group [18 (4) vs. 21 (4), p = 0.006], and no significant differences were seen in any of the other parameters. CONCLUSIONS: Compared to VM, HFNC ameliorated oxygenation function and decreased patients' effort in breathing. The hemodynamic state did not differ between HFNC and VM. Therefore, HFNC can be used safely in cardiovascular surgical patients. TRIAL REGISTRATION: This trial was registered with the UMIN Clinical Trials Registry (ID UMIN000016572).

Multiple Cardiovascular Diseases or Risk Factors Increase the Severity of Coronavirus Disease 2019.

BACKGROUND: This study aimed to determine whether disease severity varied according to whether coronavirus disease 2019 (COVID-19) patients had multiple or single cardiovascular diseases and risk factors (CVDRFs).Methods and Results:COVID-19 patients with single (n=281) or multiple (n=412) CVDRFs were included retrospectively. Multivariable logistic regression showed no significant difference in the risk of in-hospital death between groups, but patients with multiple CVDRFs had a significantly higher risk of acute respiratory distress syndrome (odds ratio: 1.75, 95% confidence interval: 1.09-2.81). CONCLUSIONS: COVID-19 patients with multiple CVDRFs have a higher risk of complications than those with a single CDVRF.

Evaluation of the Fourth-Generation FloTrac/Vigileo System in Comparison With the Intermittent Bolus Thermodilution Method in Patients Undergoing Cardiac Surgery.

OBJECTIVES: The aim of this study was to evaluate the accuracy, precision, and trending ability of the fourth-generation FloTrac/Vigileo system (version 4.00; Edwards Lifesciences, Irvine, CA) by comparing cardiac output derived from FloTrac/Vigileo system (COAP) with that measured by a pulmonary artery catheter (COTD), and to determine the effects of hemodynamic variables on the bias between COTD and COAP. DESIGN: A prospective study. SETTING: University hospital. PARTICIPANTS: Thirty patients undergoing elective cardiac surgery using cardiopulmonary bypass. INTERVENTIONS: Including hemodynamic variables, COTD and COAP were measured simultaneously at the following 10 time points: after the induction of anesthesia, at the start of operation, after sternotomy, before and after the administration of heparin, before and after the administration of protamine, at the start of sternal closure, at the end of operation, and on arrival to intensive care unit. MEASUREMENTS AND MAIN RESULTS: In total, 280 pairs of datasets were obtained. Bland-Altman analysis showed a bias of -0.41 L/min, a precision of 0.72 L/min, and limits of agreement of -1.85 and 1.03 L/min, with a percentage error of 37.1%. The concordance rate determined by 4-quadrant plot analysis and the polar concordance rate were 76% and 79%, respectively. The linear mixed-effect model revealed that the bias was influenced strongly by the difference in pulse pressure between the radial and femoral artery (p < 0.001), and the systemic vascular resistance index (p < 0.001). CONCLUSION: The fourth-generation FloTrac/Vigileo system still lacks accuracy and trending ability in cardiac surgery, and the discrepancy in cardiac output measurement depends on the peripheral vascular tone. Further improvement of this system is needed.

[Efficacy of Transversus Abdominis and Rectus Sheath Blocks in Combination with Continuous Intravenous Fentanyl for Postoperative Analgesia of Laparoscopic Colectomy: A Retrospective Study].

BACKGROUND: Ultrasound-guided transversus ab- dominis plane (TAP) and rectus sheath (RS) blocks are peripheral nerve blocks that diminish somatic pain of the abdominal wall and are useful for postoperative analgesia. Here, we retrospectively compared the effi- cacy of ultrasound-guided TAP and RS blocks in com- bination with continuous intravenous fentanyl for postoperative analgesia of laparoscopic colectomy. METHODS: The ethics committee of our institute ap- proved the study. In our hospital, postoperative analge- sia is performed with continuous intravenous fentanyl administration at three concentrations : 12.5, 18.75, and 31.25 µg · hr⁻¹. TAP and RS blocks were applied using 30-40 ml of 0.19-0.25% ropivacaine. We selected 43 patients who underwent laparoscopic colectomy from May to October 2015. We compared the fentanyl only group (F group, n=26) and block combination group (F+B group, n=17). Statistical analysis was performed with the Mann-Whitney U test P<0.05 was considered significant Results : Patient characteristics including age, height, body weight, duration of anesthesia, and surgery did not significantly differ between the two groups. The concentration of intravenous fentanyl was significantly lower in the F+B group than in the F group (F group : 19.5±8.4µg · hr⁻¹, F+B group : 14.7?4.9 µg · hr⁻¹, P=0.02). In the present study, TAP and RS blocks significantly reduced the dose of administered fentanyl. - Conclusions : Our findings suggest that a combina- tion of TAP and RS blocks lower the dose of continu- ous intravenous fentanyl needed, and may provide better postoperative analgesia after laparoscopic colec- tomy.

[A Case of Lethal Atypical Takotsubo Cardiomyopathy Detected by Sustained Ventricular Arrhythmia Just before Induction of General Anesthesia].

A 73 year-old female patient was scheduled for lumbar peritoneal shunt three weeks after subarachnoid hemorrhage. Before induction of general anesthesia, her ECG showed ventricular tachycardia (VT) without any complaints. Administration of lidocaine and direct current shocks were ineffective and VT continued. Operation was postponed and transthoracic echocardiography revealed diffuse hypokinesis. Emergent angiogram revealed midventricular ballooning with slight hypoki- nesis in basal and apical regions without significant coronary artery lesion. Atypical takotsubo cardiomyopathy was diagnosed. Intra aortic balloon pumping and continuous infusion of amiodaron and catecholamines were started, but her ventricular motion decreased. She died next morning. In this case, the physical/psychological stress before operation was con- sidered to be a trigger of the event. Although tako- tsubo cardiomyopathy is usually a transient disease, it must be kept in mind that an acute and lethal case with no response to any treatment like ours exists.

[Anesthetic Management for Lobectomy in a Patient with Pulmonary Arterial Hypertension].

Pulmonary arterial hypertension (PAH) is a known risk factor of perioperative complications, but the risks for non-cardiac operations have not yet been examined sufficiently. We report a case of a right lower lobectomy in a patient with PAH. A 73-year-old woman with Sjögren's syndrome was scheduled for right lowr lobectomy for primary lung cancer under general anesthesia. She was diagnosed with symptomatic PAH (estimated mean pulmonary arterial pressure, 40 mmHg) and medicated with ambrisentan. After induction of general anesthesia with propofol and fentanyl, a pulmonary artery catheter was placed to measure pulmonary artery pressure. The Pp/Ps was roughly 0.4 and the pulmonary artery clamp elevated it to 0.5. Milrinone administration gradually improved the Pp/Ps to 0.3. To avoid pulmonary artery pressure elevation during emergence of anesthesia, continuous dexmedetomidine was administered. The double-lumen tracheal tube was extubated uneventfully with minimal elevation in pulmonary arterial pressure.

[Anesthetic Management of Acute Pulmonary Thrombus Trapped in a Patent Foramen Ovale Detected by Transesophageal Echocardiography].

We report a case of intracardiac thrombus detected by transesophageal echocardiography (TEE). A 61-year-old man with pulmonary embolism was trans- ferred to our hospital presenting with severe respira- tory distress. Emergency surgery was scheduled to remove the thrombus identified in the right atrium by transthoracic echocardiography (TEE). Four-chamber view TEE confirmed penetration of a patent foramen ovale (PFO) to the left atrium by a thrombus ; there was no thrombus in the right ventricle or pulmonary artery. Cardiopulmonary bypass was safely established without deep hypothermic circulatory arrest and the thrombus was removed uneventfully. Subsequent TEE confirmed the absence of the thrombus. In the present case, preoperative TEE was unable to reveal the thrombus trapped in the PFO. TEE is more sensitive in identifying precise information regarding the exis- tence of thrombi. Moreover, contrast echocardiography may help detect right-to-left shunting through a PFO.

[Anesthetic Management of a Pediatric Case of Blue Rubber Bleb Nevi Syndrome Combined with Small-intestinal Intussusception].

We report the anesthetic management of a pediatric case of blue rubber bleb nevi syndrome combined with small-intestinal intussusception. A 2-year-old girl was transferred to our hospital for small-intestinal intussusception. Emergent ablation of the upper gastrointestinal tract nevus under general anesthesia was planned. Given the presence of several nevi in the oral and pharyngeal space, we utilized the McGRATH MAC (McGRATH; Aircraft Medical Ltd, United Kingdom) laryngoscope for gentle and stress-free tracheal intubation. The venous line was kept patent preoperatively, and rapid-sequence intubation was performed with the McGRATH (size 2 pediatric blade). A 4.5-mm tracheal tube was inserted uneventfully under direct visualization. The trachea was observed and the tube maintained in a proper position with a bronchofiberscope. During the procedure, cuff volume was regulated to avoid excessive increase by upper gastrointestinal endoscope insertion. The girl was extubated in the operating room and showed no postoperative complications such as hemorrhage or hoarseness.

[Anesthetic Management of Video-assisted Left Upper Lobectomy in a Patient with Ischemic Heart Disease Using an Intraaortic Balloon Pump].

We report the successful anesthetic management of video-assisted left upper lobectomy in a patient with ischemic heart disease using an intra-aortic balloon pump (IABP). An 81-year-old man with severe ischemic heart disease was scheduled for partial lobectomy for suspected lung cancer under general anesthesia. Although he had severe ischemic heart disease, coronary intervention such as percutaneous cardiac intervention or coronary artery bypass grafting was impossible due to severe coronary stenosis. IABP was instituted through the femoral artery before inducing anesthesia. Tracheal intubation was performed with the McGRATH MAC videolaryngoscope to minimize stress. Surgery was performed uneventfully and the patient was transferred to the intensive care unit under sedation. IABP was removed three hours postoperatively. After confirming no ischemic or vital sign changes, he was extubated the next day. No complications resulting from the IABP were observed.

[Anesthetic Management of Simultaneous Right Lobectomy and Esophagectomy with a Double-lumen Tracheal Tube and Bronchial Blocker].

Anesthestic management with prolonged one-lung ventilation is difficult, especially when the patient continues smoking habit. Here, we report a successful one-lung ventilation and protection with combined use of double-lumen endotracheal tube and bronchial blocker. A 68-year-old man (height 153 cm; weight, 45 kg) was scheduled for simultaneous surgery of right lobectomy and esophagectomy. He kept smoking to the operation day. To protect the ventilated lung, we guided the bronchial lumen of the DLT to the left bronchus under fiberoptic bronchoscope (FOB) guide and inflated the bronchial cuff. Next, we inserted the bronchial blocker from the tracheal lumen of the DLT and inflated the cuff in the left bronchus under FOB guidance. We performed continuous suctioning of the right trachea via the inner lumen of BB. During the operation, non-negligible amount of blood and sputum was aspirated from the inner lumen of the BB. Furthermore, there was no visible blood inflow in the left bronchus. We could protect the ventilated lung with double cuff, i. e. bronchial cuff of DLT in the left bronchus and BB cuff in the right bronchus. Simultaneous operation was uneventfully performed and no oxygenation or ventilation trouble was observed during the operation.

Laryngoscopy facilitates successful i-gel insertion by novice doctors: a prospective randomized controlled trial.

BACKGROUND: This study investigated the hypothesis that the efficacy of insertion of the supraglottic device i-gel(®) (i-gel) can be improved by laryngoscopy and can provide better sealing pressure in anesthetized patients by novice doctors. METHODS: Eighty-four adult patients were assigned to the laryngoscopy group (L group, 42 patients) or control group (i.e., conventional blind insertion; C group, 42 patients). Anesthesia was induced with propofol and remifentanil, and rocuronium 0.6-0.9 mg/kg was administered. The number of attempts until successful insertion, sealing pressure, vital sign changes upon insertion, and subjective difficulty of insertion by novice doctors were compared between the groups. RESULTS: The total number of insertion attempts was one (L group 36 cases, C group 23 cases), two (L group 6 cases, C group 18 cases), and three (L group 0 case, C group 1 case), with significant differences between groups (P = 0.007). The sealing pressure was significantly higher in the L group than in the C group (L group 22.3 ± 2.6 cmH2O, C group 19.5 ± 2.7 cmH2O, P < 0.001). Vital sign changes (heart rate and blood pressure) did not differ between the two groups. The subjective difficulty of insertion was significantly lower in the L group than in the C group (L group 26.8 ± 11.8 mm, C group 47.0 ± 15.1 mm, P < 0.001). The incidence of postoperative pharyngeal pain was significantly lower in the L group than in the C group (P < 0.001), while the incidence of hoarseness did not differ between the two groups (P = 1.00). CONCLUSION: Our results suggest that laryngoscopy facilitates i-gel insertion by novice doctors, as reflected in the rate of successful insertions, higher sealing pressure, and lower subjective difficulty of insertion in anesthetized patients.

[A Case of Septic Shock Immediately following Cesarean Section].

Here we report a case of severe septic shock immediately following cesarean section. A pregnant woman with dichorionic diamniotic twins was diagnosed with preterm rupture of membranes (PROM). Ritodrine hydrochloride and betamethasone did not sufficiently relieve abdominal extension; emergency cesarean section was scheduled 4 days later, at 31 week 5 day gestation. The patient did not show any symptoms or laboratory data suggesting infection. Spinal anesthesia was initiated with 2.2 ml of 0.5% bupivacaine hydrochloride and fentanyl 10 µg at L3-4; sensory loss (T3) was confirmed. Epidural anesthesia at L1-2 was performed for postoperative pain control. Surgery proceeded uneventfully, but the first baby did not respond to neonatal CPR. One hour after surgery, the patient showed signs of shock and a fever of 40.9 degrees C. Catecholamine and antibiotics relieved her symptoms. Retrograde infection of Escherichia coli was attributed to fetal distress and septic shock. Early phase septic shock should be considered in pregnant women with PROM.

[Development of Takotsubo Cardiomyopathy during Recovery from General Anesthesia: A Case Report].

Takotsubo cardiomyopathy is a cardiac syndrome characterized by transient left ventricular dysfunction. A 61-year-old woman underwent laparoscopic cholecystectomy under general anesthesia. During recovery from general anesthesia, several arrhythmias occurred without cardiac collapse following desflurane discontinuation and sugammadex sodium administration. She had a chest pain after extubation, with ST segment elevation in leads aV(L) and V2-4. Emergency left ventricular angiogram revealed no significant coronary stenosis, and excessive contraction of the base and severe hypokinesis of the apex suggested Takotsubo cardiomyopathy. Sympathetic hyperactivity during acute recovery from anesthesia with desflurane discontinuation and muscle relaxant reversal with sugammadex sodium was considered the likely cause of Takotsubo cardiomyopathy.

[Rapid Sequence Intubation with the McGRATH MAC Videolaryngoscope in the Sitting Position for a Patient with Restricted Mouth Opening].

Here we report successful rapid-sequence inubation with the McGRATH MAC videolaryngscope (McGRATH) in the face to face sitting position for a patient with severe ileus and restricted mouse opening. A 46-year-old woman with advanced bladder cancer had developed ileus. Ileus tube and octreotide did not relieve her symptoms, and emergency colostomy was planned. Due to the invasion of cancer to the spine and interior of the pelvis, she could not keep supine position and always kept sitting position. We decided to perform rapid-sequence intubation in the sitting position. First an anesthesiologist stood at face to face position to the patients, and the second anesthesiologist kept the head of the patient from the cranial side. After thiamylal and fentanyl administration, cricoid pressure was applied by the third anesthesiologist. Under the guide of the McGRATH's monitor, we could successfully insert the 7.0 mm internal diameter tracheal tube with a stylet uneventfully in the face to face sitting position.

[Anesthetic Management of Right Lower Lobectomy in a Patient with Marfan Syndrome].

We report a case of partial lobectomy in a patient with Marfan syndrome. A 56-year-old woman with Marfan syndrome was scheduled for partial lobectomy for suspected lung cancer under general anesthesia. She underwent a Bentall operation and mitral valve replacement 10 months before and strict blood pressure management was required. After induction of general anesthesia with propofol and fentanyl, topical intratracheal lidocaine anesthesia was performed using the Pentax-AWS Airwayscope (AWS) for visualization, allowing for the Soft-tipped Tube Exchanger (TE-Soft) to be inserted into the trachea. Next, a double-lumen tracheal tube was uneventfully intubated via the TE-Soft with minimal change in vital signs. During the operation, pressure-controlled ventilation was performed to minimize the risk of pneumothorax. After the operation, under continuous administration of landiorol and dexmedetomidine, the double-lumen tracheal tube was extubated uneventfully. Strict airway and circulation management is needed for lung or vessel preservation in patients whose conditions are complicated by Marfan syndrome.

[Successful Resuscitation from Cardiac Arrest due to Pulmonary Artery Rupture Utilizing Cardiopulmonary Bypass].

We report a case of successful resuscitation from cardiac arrest due to pulmonary artery rupture utilizing cardiopulmonary bypass. A 79-year-old man was diagnosed with lung cancer; segment resection of the upper lung was scheduled under general anesthesia. Anesthesia was induced uneventfully and surgery began in the right lateral position. During lung resection, the pulmonary artery was ruptured and led to cardiac arrest with pulseless electrical activity. Astriction, volume overload, and hypertensive medication led to vital sign recovery. Percutaneous cardiopulmonary support was achieved with improvements in the blood flow of the femoral vein and artery. Yet, bleeding from the ruptured artery did not stop. Cardiopulmonary bypass with pulmonary artery blood removal and femoral artery blood transmission stopped the bleeding of the damaged part, leading to the repair of the artery. Rapid establishment of cardiopulmonary bypass may be useful in cases of pulmonary artery damage.

[Successful Tracheal Intubation Using Videolaryngoscope in an Infant with Massive Tongue Swelling].

We report use of videolaryngoscope for difficult airway management in an infant with severe tongue swelling after laceration repair. A 3-month-old male infant was transferred to our hospital for respiratory difficulty. He could not open his mouth sufficiently, and the examination revealed massive swelling of the left side of the tongue. Emergent surgical repair of the tongue was scheduled, anticipating a difficult airway. The venous line was kept patent preoperatively, and 8% sevoflurane was administered maintaining spontaneous ventilation. We then inserted the Pentax Airway Scope with an infant-sized Intlock (AWS-I) from the right side of the mouth and obtained a good view at laryngoscopy. A 3.5-mm tracheal tube was passed uneventfully under the view of AWS-I. The AWS-I is useful for difficult airway management in infants, preserving spontaneous ventilation.

Clinical comparison of an echocardiograph-derived versus pulse counter-derived cardiac output measurement in abdominal aortic aneurysm surgery.

OBJECTIVE: To compare cardiac output (CO) measurements acquired using the Flotrac/Vigileo system (Edwards Lifesciences, Irvine, CA) and CO measured by transesophageal echocardiography using the product of the aortic valve area, the time integral of flow at the same site, and the heart rate during abdominal aortic aneurysm (AAA) surgery. DESIGN: A prospective clinical study. SETTING: Cardiac surgery operating room of 1 heart center hospital. PARTICIPANTS: Twenty patients undergoing elective AAA surgery. INTERVENTIONS: CO was determined simultaneously using the Flotrac/Vigileo system (CO(AP)) and transesophageal echocardiography (CO(TEE)) as the reference method at 8 time points during AAA surgery. MEASUREMENTS AND MAIN RESULTS: One hundred sixty simultaneous datasets were obtained. The authors observed a significant correlation between CO(AP) and CO(TEE) values (R = 0.56, p < 0.001). Bland-Altman analysis of CO(AP) and CO(TEE) showed a bias of 0.12 L/min and limits of agreement from -1.66 to 1.90 L/min, with a percentage error of 41%. Just after aortic clamping, CO(AP) significantly increased, but CO(TEE) decreased in comparison with previous measurements. There was a significant association among changes in CO(AP) and pulse pressure, heart rate, and central venous pressure (CVP). However, changes in CO(TEE) were only associated with variations in heart rate. CONCLUSIONS: CO(AP) values were not clinically acceptable for use in AAA surgery because of wide variations during aortic clamping and declamping. Changes in pulse pressure, heart rate, and CVP were associated with significant changes in CO(AP), whereas only changes in heart rate showed associated changes in CO(TEE).

PaO2 / FiO2 ratio responsiveness to prone positioning in intubated patients with severe COVID-19: a retrospective observational study.

Aim: Prone positioning of coronavirus disease 2019 (COVID-19) patients could improve oxygenation. However, clinical data on prone positioning of intubated COVID-19 patients are limited. We investigated trends of PaO2 / FiO2 ratio values in patients during prone positioning to identify a predictive factor for early detection of patients requiring advanced therapeutic intervention such as extracorporeal membrane oxygenation (ECMO). Methods: This retrospective, observational cohort study was undertaken between April 2020 and May 2021 in a tertiary referral hospital for COVID-19 in Osaka, Japan. We included intubated adult COVID-19 patients treated with prone positioning within the first 72 h of admission to the intensive care unit and followed them until hospital discharge or death. Primary outcomes were in-hospital mortality and escalation of care to ECMO. We used unsupervised k-means clustering modeling to categorize COVID-19 patients by PaO2 / FiO2 ratio responsiveness to prone positioning. Results: The final study cohort comprised 54 of 155 consecutive severe COVID-19 patients. Three clusters were generated according to trends in PaO2 / FiO2 ratios during prone positioning (cluster A, n = 16; cluster B, n = 24; cluster C, n = 14). Baseline characteristics of all clusters were almost similar. Cluster A (no increase in PaO2 / FiO2 ratio during prone positioning) had a significantly higher proportion of patients placed on ECMO or who died (6/16, 37.5%). Numbers of patients with ECMO and with in-hospital death were significantly different between the three groups (p = 0.017). Conclusion: In Japanese patients intubated due to COVID-19, clinicians should consider earlier escalation of treatment, such as facility transfer or ECMO, if the PaO2 / FiO2 ratio does not increase during initial prone positioning.

Toward a Practical Impedimetric Biosensor: A Micro-Gap Parallel Plate Electrode Structure That Suppresses Unexpected Device-to-Device Variations.

We propose a rational electrode design concept for affinity biosensors based on electrochemical impedance spectroscopy to substantially suppress unexpected device-to-device variations. On the basis that the uniformity of the current distribution affects the variation, a novel micro-gap parallel plate electrode (PPE) was developed, where two planar electrodes with edges covered with a SiO2 layer were placed face to face. The structure provides a uniform current distribution over the planar electrode surface and maximizes the contribution of the planar electrode surface to sensing. For a comparative study, we also fabricated a micro-structured interdigitated electrode (IDE) that has been widely adopted for high-sensitivity measurement, although its current is highly concentrated on the electrode edge corner. Protein G (PrG) molecules were immobilized on both electrodes to prepare an immunoglobulin G (IgG) biosensor on which the specific binding of PrG-IgG can occur. We demonstrated that the IgG sensor with the PPE has small device-to-device variations, in strong contrast to the sensor with the IDE having large device-to-device variations. The results indicate that the current distribution on the electrode surface is important to fabricating electrochemical impedance spectroscopy biosensors with small device-to-device variations. Furthermore, it was found that the PPE allows ultrasensitive detection, that is, the sensor exhibited a linear range from 1 × 10-13 to 1 × 10-7 mol/L with a detection limit of 1 × 10-14 mol/L, which is a record sensitivity at low concentrations for EIS-based IgG sensors.